Chain saw oiling system

ABSTRACT

A chain saw oiling system comprises an automatic pump for continuously pumping oil from a reservoir to the saw chain of a chain saw and the manual pump adapted to prime the automatic pump, to purge foreign matter from the system, and to supply additional oil whenever the output of the automatic pump is insufficient for the proper lubrication of the saw chain. Both of the pumps are mounted in a pump housing which is detachably secured to the chain saw. The automatic pump comprises a relatively small piston and a diaphragm which is actuated by pressure pulses developed in the crankcase in the engine of the chain saw to continuously reciprocate the piston. The manual pump is located upstream from the automatic pump and comprises a relatively large piston adapted for manual reciprocation.

United States Patent McDermott 1 CHAIN SAW OILING SYSTEM [58] FieldInventor:

Assignee:

Filed:

Appl.

John W. McDermott, Shreveport, La.

Beaird-Poulan, 1nc., Shreveport, La.

Oct. 25, 1972 US. Cl 123/196 CP, 83/169, 184/28,

Int. Cl. Fl6n 13/08, FOlm 1/04 of Search 184/15 R, 26, 28, 29; 123/196CP; 83/169 References Cited UNITED STATES PATENTS [4 1 Feb. 11, 1975Primary Examiner-Mauel A. Antonakas Attorney, Agent, or Firm-1-1ubbard,Thurman, Turner & Tucker 57 ABSTRACT A chain saw oiling system comprisesan automatic pump for continuously pumping oil from a reservoir to thesaw chain of a chain saw and the manual pump adapted to prime theautomatic pump, to purge foreign matter from the system, and to supplyadditional oil whenever the output of the automatic pump is insufficientfor the proper lubrication of the saw chain. Both of the pumps aremounted in a pump housing which is detachably secured to the chain saw.The automatic pump comprises'a relatively small piston and a diaphragmwhich is actuated by pressure pulses developed in the crankcase in theengine of the chain saw to continuously reciprocate the piston. Themanual pump is located upstream from the automatic pump and comprises arelatively large piston adapted for manual reciprocation.

13 Claims, 5 Drawing Figures [U FEB] l 1373 SHEEI 3 OF 3 FIG.

FIG

FIG.5

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to achain saw oiling system, and more particularly to a system for oilingsaw chains including both an automatic pump and an auxiliary manualpump.

As is well known, chain saws typically comprises a saw chain which isdriven around a guide bar by an inter-nal combustion engine. In theoperation of such a saw it is desirable to apply oil to the saw chain ona more or less continuous basis. This is necessary not only to lubricatethe saw chain in its movement around the guide bar, but also to preventundue accumulations of sawdust, sap, etc., on the saw chain.

Various systems for oiling saw chains have been provided heretofore.Thus, systems incorporating a separate pump driven directly by theengine of the chain saw have been provided, as have systems wherein thepump incorporates one or more parts of the engine, such as thecrankshaft. In chain saws incorporating two cycle engines, crankcasepressure has also been utilized to force oil to the saw chain. Thelatter systems typically comprise means for pressurizing an oilreservoir to cause oil flow to the saw chain, and an auxiliary pumpadapted to force oil through the oil passageway should it becomeblocked.

Notwithstanding the foregoing and other attempts at providing a workablechain saw oiling system a number of problems have remained unsolved.Thus, particu larly in the case of the small, lightweight type of chainsaw that is popular at the present time, the crankcase and other majorcomponents of a chain saw often comprise relatively complicated diecastings. It has been found that if the chain saw oiling system isintegrated into these components, leaks can develop in the oiling systemwhich are difficult if not impossible to isolate. Such a leak can impedeor even completely prevent the proper operation of the chain saw oilingsystem. Also, even if a leak is located, it may be impossible to correctwithout replacing one or more major castings.

The present invention comprises a novel chain saw oiling system whichovercomes the foregoing and other difficulties that have long beenassociated with the prior art. In accordance with the broader aspects-ofthe invention the oiling system includes an automatic pump comprising adiaphragm mounted in a pump housing which is detachably secured to achain saw. The diaphragm is actuated by pressure pulses developed in thecrankcase of theengine of the chain saw, and functions to reciprocate afirst piston in a first pumping cylinder formed in the pump housingwhenever the engine is running. By this means oil'is continuously pumpedfrom an oil reservoir through an inlet passageway, through an oilpassageway formed in the pump housing, and through an outlet passagewayto the saw chain of the chain saw.

The chain oiling system further includes a manual pump comprising apiston mounted for reciprocation in a second pumping cylinder formed inthe pump housing. The piston of the manual pump is substantially largerthan the piston of the automatic pump, and the manual pump must belocated upstream from the automatic pump. By this means the manual pumpfunctions to prime the automatic pump, to purge foreign matter out ofthe automatic pump, and to supply additional oil whenever the quantityof oil supplied by the automatic pump is insufficient for properlubrication of the saw chain.

In accordance with more specific aspects of the invention, inlet andoutlet check valves common to both of the pumps are located at theopposite ends of the oil passageway formed in the pump housing. By thismeans any leaks that might occur are isolated at the pump housing andare therefore readily isolated and corrected. A spring is provided fornormally reciprocating the piston of the automatic pump to a positionwherein oil flow through the oil passageway is permitted under theaction of the manual pump. The diaphragm is mounted in a diaphragmchamber which communicates with the pumping cylinder of the automaticpump. A relatively large passageway extends from the crankcase of theengineto the side of the diaphragm opposite the spring for reciprocatingthe piston of the automatic pump against the action of the spring. Arelatively small passageway extends from the crankcase to the oppositeside of the diaphragm for relieving pressure in the diaphragm chamber.

DESCRIPTION OF THE DRAWINGS A more complete understanding of theinvention may be had by referring to the following Detailed Descrip tionwhen taken in conjunction with the accompanying Drawings, wherein: FIG.1 is a top'view of a chain saw utilizing an oiling system incorporatingthe invention;

FIG. 2 is a sectional view taken generally along the line 2-2 in FIG. 1;

FIG. 3 is an exploded view of the oiling system;

FIG. 4 is a sectional view taken generally along the line 4-4 in FIG. 1;and

FIG. 5 is a schematic illustration of the cooperation between thevarious component parts of the oiling systern.

DETAILED DESCRIPTION Referring now to the Drawings, and particularly toFIGS. 1 and 2 thereof, there is shown a chain saw 10 including a chainoiling system 12 constructed in accordance with the present invention.The chain saw 10 comprises a housing 14 including a handle 16. A fronthandle bar 18 is mounted on the housing 14, as is a guide bar 20. A sawchain 22 is supported for movement around the periphery of the guide bar20 under the action of an engine 24.

As is best shown in FIG. 2, the engine 24 of the chain saw 10 comprisesa piston 26 mounted for reciproca tion in a cylinder 28 having adownwardly and rearwardly extending axis 30. A connecting rod 32connects the' piston 26 to a crankshaft 34 mounted for rotation in acrankcase 36. Thus, upon reciprocation of the piston 26, the crankshaft34 is rotated about an axis Referring to FIG. 1, the crankshaft 34 ofthe chain saw 10 is coupled to the saw chain 22 through a clutch v '40and a sprocket 42. The clutch 40 is adapted for actuation by a trigger44 mounted in the handle 16, as shown in FIG. 2. Thus, upon actuation ofthe trigger 44, the sprocket 42 is operatively connected to thecrankshaft 34 through the clutch 40, whereby the saw chain 22 is drivenby the engine 24 around the periphery of the guide bar 20 to effectcutting.

The engine 24 of the chain saw comprises a two cycle engine. As is usualin such devices, the crankcase 36 of the engine 24 is utilized forinduction and precompression of the fuel/air mixture for the engine.Thus, during the compression stroke of the piston 26, a partial vacuumis established in the crankcase 36, whereby a carbureted mixture of airand liquid fuel having a lubricant mixed therewith is drawn into thecrankcase 36. During the subsequent power stroke of the piston 26, thefuel/air mixture is compressed in-the crankcase 36. Thus, when theintake valve of the engine 24 is opened, the compressed fuel/air mixtureflows rapidly from the crankcase 36 into the portion of the cylinder 28beyond the piston 26. By this means there is assured a full charge ofthe fuel/air mixture in the cylinder 28 prior to the compression strokeof the piston 26.

The crankcase 36 of the engine 24 of the chain saw 10 is defined by apair of mating die castings 46 and 48. The die castings 46 and 48 alsodefine an oil reservoir 50 which receives a quantity of oil 52 suitablefor lubricating the saw chain 22, such as a light machine oil. In theoperation of the chain saw 10, the chain oiling system 12 functions todeliver oil from the reservoir 50 to an oil outlet 56 extending to aslot 58 formed in the "guide bar. By this means oil iscontinuouslyapplied to the chain 22 of the chain saw 10, whereby the chain islubricated.

The chain oiling system 12 includes an inlet passage way 60comprising aflexible tube 62 extending through the oil reservoir 50 to an inlet 64comprising a weight 66 and'a screen 68. The weight 66 functions tomaintain proper positioning of the inlet end 64 of the tube 62 withinthe reservoir 50, and the screen'68 functions to prevent foreign matterfrom entering the chain oiling system 12. As is best shown in FIG. 1,the opposite end of the tube 6 2 is provided with.a fitting 70 mountedin an aperture 72 formed in the pump housing 74.

The operating components of the chain oiling system 12 are located in apump housing 74 which is detachably secured to the die casting 46 bymeans of a pair of screws 76 and 78. The construction and operation ofthe operating components of the chain oiling system 12 will be bestunderstood by referring to FIG. 5. It should be understood, however,that FIG. 5 is a schematic view in that the component parts of the chainoiling system have been rearranged therein for clarity of illustration.On the other'hand, the functional relationship between the componentparts of the chain oiling system 12 are consistent between FIG. 5 andthe actual construction of the system. v

The inlet passageway 60 extends to an inlet check valve 80 mountedwithin the fitting 70. The check valve 80 extends to an oil passageway82 formed in the pump housing 74. Portions of the oil passageway 82 arecommon to portions of an upstream pumping cylinder 84 and a downstreampumping cylinder 86. The downstream pumping cylinder 86 is formed ina-barrel 88 which is mounted in the bore 90 formedin the pump housing74.

The barrel 88 further comprises a circumferential groove 92 and at leastone radially extending hole, 94,.

whereby oil flowing through the passageway 82 is received in thedownstream pumping cylinder 86. An

outlet check valve 96 is mounted in the lower end of a circumferentialgroove 100. The groove 100 extends to an oil outlet passageway 102.

Referring momentarily to FIGS. 1, 2 and 4, the oil outlet passageway 102of the chain oiling system 12 comprises a fitting 104 which functions tosecure one end of a flexible conduit l06'to the pump housing 74. Asimilar fitting 108 is utilized to secure the opposite end of theconduit 106 to the housing 14 of the chain saw 10. By this means oilpassing through the chain oiling system 12 is directed to the outlet 56and into the slot 58, whereby the saw chain 22 is lubricated.

Returning again to FIG. 5, a piston 110 is supported for reciprocationin the downstream pumping cylinder 86. A diaphragm chamber 112 is formedin the pump housing 74 and extends into communication with thedownstream pumping cylinder 86. A flexible diaphragm 114 extends throughthe diaphragm chamber 112. A pair of opposed plates 116 and 118 aremounted on opposite sides of the diaphragm 114 and function to common tothe downstream pumping cylinder 86 is opened to permit the passage ofoil therethrough'.

A passageway 122 extends from the crankcase 36 of the engine 24 of thechain saw 10 into the pump housing 74. The passageway 122 includes aportion 124 having a relatively large cross-sectional'area'which extendsto' the portion of the diaphragm chamber 112 on the oppoiste side of thediaphragm 114 from the spring 120. By this means positive and negativepressure" pulses which are generated in the crankcase 36 due to thereciprocation of the piston 26 of the engine 24 act on the diaphragm 114and thereby function to reciprocate the piston 110 into the portion ofthe downstream pumping cylinder 86 which is common to the oil passageway82. By this means oil is forced out of the pumping cylinder 86 throughthe outlet check valve 96 and through the discharge passageway 102"tothe slot 58, whereby the oil isavailable for lubrication of the sawchain 22. I

The passageway 122 extending from the crankcase 36 further includes aportion 126 which is substantially smaller in cross-sectional area thanthe portion 124. The purpose of the passageway 126 is to equalize thepressure on the opposite side of the diaphragm chamber 112, therebyfacilitating outward reciprocation of the piston 110 .under the combinedaction of negative pulses and of the spring 120. It has been found thatsuperior operating results are accomplished in the chain oiling system12 when the passageway 126 is utilized.

A piston 130 is supported for reciprocation in the upstream pumpingcylinder 84.. The piston 130 includes a packing member 132 and isnormally positioned as shown in FIG. 5 by a spring 134. By this meansthe portion of the oil passageway 82 which is common to the upstreampumpingcylinder 84 is normally open to permit the passage of oiltherethrough under the action of the piston 110. i

The piston 130 is adapted for manual actuation. Thus, an actuator 136extends from the piston 130 through a seal 138 to a pushbutton 140. Asis best shown in FIG. 2, the pushbutton 140 protrudes from the top ofthe handle 16 of the housing 14 of the chain saw 10. By this means thepushbutton 140 is adapted for actuation by the thumb of the hand of anoperator which engages the handle 16 and having a finger engaging thetrigger 44.

The manually actuated piston 130 serves three functions in the chainoiling system 12. First, although the piston 110 is self-priming, theautomatic pump of the chain oiling system may be primed more rapidly byusing the manual pump.

Second, the piston 110 is reciprocated continuously and very rapidlyduring the operation of the chain saw 10. This means that the piston 110and the downstream pumping cylinder 86 must be small in diameter inorder to maintain the volume of oil flow from the reservoir 50 to theslot 58 within reasonable limits. By the same token, the small size ofthe piston and the cylinder 86 means that the cylinder 86 is easilyclogged by foreign matter. In such a case the manual pump of the chainoiling system may be utilized to force a substantial volume of oilthrough the automatic pump, whereby any foreign materials which may haveaccumulated in the downstream. pumping cylinder are purged therefrom.

Finally, it will be understood that no adjustments are provided in thechain oiling system 12 for controlling the volume of oil flow under theaction of the automatic pump. Instead it is deemed preferable topreadjust the automatic pump to supply that quantity of oil which isrequired to lubricate the chain 22 under normal operating circumstances.Then, in those instances in which additional oil is required in order toproperly lubricate the saw chain, the manual pump of the chain oilingsystem is periodically actuated to furnish the necessary additional oil.

The various structural details of the chain oiling system 12 will bebest understood by referring to FIG. 3. Oil is received in the pumphousing 74 from the fitting 70 of the inlet passageway 60 through agasket 142 and an inlet port formed on the same side of the housing asthe inlet port of the passageway 122. The upstream pumping cylinder 84extends perpendicularly with respect to the downstream pumping cylinder86. This positions the piston 130 for actuation by the pushbutton 140operating through the actuator 136. The small portion 126 of thepassageway 122 comprises a slot formed in the pump housing 74.

The diaphragm chamber 112 of the chain oiling systern 12 is defined bythe pump housing 74 and a cap 144 which is secured to the pump housing74 by the screw 78 and a screw 146. A gasket 148 is provided between thediaphragm 114 and the pump housing 12. The passageway 122 includesapertures 150 and 152 extending through the gasket 148 and the diaphragm114.

One of the important advantages resulting from the use of the presentinvention will now be more easily understood. The entire inletpassageway 60 is positioned beneath the surface of the quantity of oil52 and the reservoir 50. This completely prevents leakage of air intoany portion of the inlet passageway. All of the operating components ofthe chain saw oiling system 12 are mounted within the pump housing 74.Thus, any leakage of air into these components must occur through theseal 138, the gasket 142 or the gasket 148. Such leaks are thereforeeasily isolated and corrected. Also, should it prove impossible tocorrect any such leak, the entire pump housing 174 and the componentparts mounted therein may be removed by removing the screws 76 and 78.By this means all of the operating components of the chain saw oilingsyste m may be replaced without disturbing any of the components of thechain saw 10 per se. i

Although particular embodiments of the inventio have been illustrated inthe accompanying drawings and described in the foregoing DetailedDescription, it will be understood that the invention is not limitedtothe embodiments disclosed, but is capable of numerous rearrangements,modifications and substitutions of parts and elements without departingfrom the spirit of the invention.

What is claimed is:

1. in a chain saw of the type including a saw chain and an engine fordriving the saw chain and having a crankcase for the induction andprecompression of a fuel/air mixture, an automatic chain oiler.comprising:

a pump housing including an oil passageway, a pumping cylinder includinga portion common to a portion of the oil passageway, and a diaphragmchamber communicating with the pumping cylinder;

inlet and outletcheck valve means mounted at the opposite ends of theoil passageway;

a piston mounted in the pumping cylinder for reciprocation in thecylinder to pump oil through the oil passageway;

a diaphragm mounted in the diaphragm chanber and connected to thepiston;

means for admitting pressure pulses from the crankcase of the engine toa first side of the diaphragm in the diaphragm chamber thereby actuatingthe diaphragm to reciprocate the piston in the pumping cylinder; and

means for relieving pressure from a side of the diaphragm opposite thefirst side to assist the diaphragm to reciprocate the piston in thecylinder,

said piston being mounted on the diaphragm to respond directly to thepressure pulses by reciprocating through a pumping cycle with eachpressure pulse admitted to the diaphragm.

2. A chain saw oiler comprising:

a pump housing detachably secured to a chain saw and including an oilpassageway extending from one end of the housing to the other, anupstream pumping cylinder having a portion of the oil pas sagewayextending through it, a downstream pumping cylinder having a portion ofthe oil passageway extending through it, and a diaphragm chambercommunicating with the downstream pumpimg cylinder;

inlet and outlet check valve means mounted at the opposite ends of theoil passageway of the pump housing;

a piston mounted in the upstream pumping cylinder for manualreciprocation to pump oil through the oil passageway including theportions extending through the upstream and downstream pumpingcylinders;

a piston supported for reciprocation in the downstream pumping cylinderto force oil through the oil passageway;

a diaphragm mounted in the diaphragm chamber and connected to thedownstream piston; and

means for admitting pressure pulses from the chain saw to a first sideof the diaphragm in the diaphragm chamber and for relieving pressurefrom a side of the diaphragm opposite the first side thereby actuatingthe diaphragm to reciprocate the downstream piston whenever the chainsaw is operating, said piston being mounted on the diaphragm to responddirectly to the pressure pulses by reciprocating through a pumping cyclefor each pressure pulse introduced to the diaphragm.

3. The chain saw oiler according to claim 2 further including:

an oil reservoir mounted on the chain saw;

an oil inlet passageway extending from the reservoir to the inlet checkvalve means; and

an oil outlet passageway extending from the outlet check valve means tothe chain of the chain saw, said outlet check valve means including acheck valve in the portion of the oil passageway extending through thedownstream pumping cylinder for admitting oil to the oil outletpassageway with each reciprocation of the pistons in the upstream anddownstream pumping cylinders.

4 In a chain saw of the type including a saw chain and a two-cycleengine for driving the saw chain and having a crankcase for inductionand precompression of a fuel/air mixture, a chain oiler comprising;

an oil reservoir;

an oil inlet passageway including I a weighted, screened inlet portpositioned in the oil reservoir and a flexible conduit extending fromthe inlet port to an inlet check valve;

a pump housing detachably secured to the chain saw and including meansfor receiving oil from the inlet passageway through the inlet checkvalve;

an oil passageway extending through the pump housmg; a

a'pair of pumping cylinders formed in the pump housing and eachincluding a portion of the oil passageway whereby oil flowing throughthe oil passageway flows through portions of both of the pumpingcylinders in series;

a piston mounted in the upstream oil passageway for reciprocation intoand out of the portion of the upstream pumping cylinder common to theoil passageway to pump oil through the passageway;

a piston mounted in the downstream pumping cylinder for reciprocationinto andv out of the portion of the downstream pumping cylinder commonto the oil passageway to pump oil through the passage-' way;

spring means for normally reciprocating the downstream piston out of theportion of the downstream pumping cylinder.common to the oil passagewayand thereby permitting the flow of oil through the pump housing underthe action of the upstream piston;

a diaphragm chamber formed in the pump housing and communicating withthe downstream pumping cylinder;

a diaphragm mounted in the diaphragm chamber and I outlet check valvemeans mounted on the pump housing at the opposite end of the oilpassageway from the inlet check valve; and I an outlet passagewaycomprising a conduit extending from the outlet check valve means to apoint adjacent the path of travel of the saw chain.

5. The chain oiler according to claim 4 wherein the downstream piston isoperated substantially continuously by pressure pulses from thecrankcase of the engine to pump lubricating oil from the oil reservoirto the saw chain in sufficient quantity to properly lubricate the sawchain under normal operating circumstances, and wherein the upstreampiston comprises a relatively large piston adapted for manual operationto prime the downstream pumping cylinder, to purge foreign matter out ofthe downstream pumping cylinder and to pump additional oil from thereservoir to a saw chain in those instances in which the quantity of oilpumped by the downstream piston is insufficient to properly lubricatethe chain.

6. In a chain saw of the type including a saw chain and an internalcombustion engine driving the chain and having a crankcase for inductionand precompression of the fuel mixture, the improvement comprising:

a. a pump housing having first and second cylinders, an oil passagewayformed through the housing and through the cylinders formed therein andinlet and outlet check valve means mounted at the opposite ends of theoil passageway of the housing;

b. a first pump comprising:

a piston mounted for reciprocation in said first cylinder driven bypressure pulses in the crankcase of the engine for continuously pumpingoil from an oil reservoir to the saw chain and thereby lubricating thechain,

a diaphragm-chamber formed in the pump housing and communicating withthe pumping cylinder of the first pump,

a diaphragm mounted in the diaphragm chamber and connected to the pistonof the first pump, and

means for admitting pressure pulses from the crankcase of the engine tothe diaphragm chamher and thereby reciprocating the piston of the firstpump in its pumping cylinder;

0. a second pump having a piston mounted for reciprocation in saidsecond cylinder, said second pump being located between the oilreservoir and the first pump in flow communication with the oilpassageway, and being manually actuated for priming the first pump, forpurging foreign matter out of the first pump, and for pumping additionaloil to the chain whenever the oil from the first chain pump isinsufficient to properly lubricate the chain;

d. a spring positioned between the diaphragm and the pump housing andthereby biasing the piston of the first pump for reciprocation out ofthe oil passageway to permit the flow of oil therethrough;

e. a major passageway extending through the pump housing to the side ofthe diaphragm opposite the spring whereby the diaphragm is responsive topositive pressure pulses in the crankcase to reciprocate the piston intothe oil passageway to accomplish a pumping stroke; and I f. a minorpassageway extending from the crankcase to the same side of thediaphragm as the spring whereby pressure in the diaphragm chamber isrelieved.

7. In a chain saw of the type including a saw chain and an engine fordriving the saw chain and having a crankcase for the induction andprecompression of a fuel/air mixture, an automatic chain oilercomprising:

a pump housing including an oil passageway, a pumping cylinder includinga portion common to a portion of the oil passageway, and a diaphragmchamber communicating with the pumping cylinder;

inlet and outlet check valve means mounted at the opposite ends of theoil passageway;

a piston mounted in the pumping cylinder for reciprocation into and outof the portion of the cylinder common to the oil passageway to pump oilthrough the oil passageway;

a diaphragm mounted in the diaphragm chamber and connected to thepiston;

a spring positioned in the diaphragm chamber for reciprocating thepiston out of the portion of the pumping cylinder common to the oilpassageway and thereby permitting oil through the passageway; and

means for admitting pressure pulses from the crankcase to the diaphragmchamber comprising a first relatively large passageway formed in thepump housing for directing pressure pulses from the crankcase to theopposite side of the diaphragm from the spring whereby positive pressurepulses in the crankcase acting against the diaphragm reciprocate thepiston into the portion of the pumping cylinder common to the oilpassageway against the action of the spring, and a second relativelysmall passageway formed in the housing and extending to the same side ofthe diaphragm as the spring for relieving pressure in the diaphragmchamber.

8. The chain oiler according to claim 7 further including:

a second pumping cylinder formed in the pump housing and including aportion common to a portion of the oil passageway, and

a second piston mounted in the second pumping cylinder for manualreciprocation to force oil through the oil passageway including thatportion common to the first pumping cylinder and thereby priming thefirst cylinder, clearing foreign matter from the first pumping cylinder,and supplying quantities of oil to the chain in excess of those suppliedby the operation of the first pump.

9. The chain oiler according to claim 8 further including:

an oil reservoir mounted on the chain saw;

a flexible oil conduit extending from an inlet in the oil reservoir tothe inlet check valve means; and an oil outlet conduit extending fromthe outlet check valve means to the saw chain.

10. In a chain saw of the type including a saw chain and an internalcombustion engine driving the chain and having a crankcase for inductionand precompression of the fuel mixture, the improvement comprising:

a pump housing having first and second cylinders and an oil passagewayformed through the pump housing between the cylinders and incommunication with an oil reservoir and the saw chain,

a first pump having a piston inthe first cylinder mounted to reciprocatein the first cylinder in response to cyclical pressure pulses in thecrankcase of the engine to continuously pump oil from the oil reservoirto the saw chain and thereby lubricate the chain, and

a second pump having a piston mounted for manual reciprocation in thesecond cylinder located be tween the oil reservoir and the first pump inflow communication with the oil passageway, said second pump beingselectively actuated to pump oil through the oil passageway and thefirst cylinder for priming the first pump, for purging foreign matterout of the first pump, and for pumping additional oil to the chainwhenever the oil from the first pump is insufficient to properlylubricate the chain. 7 11. The improvement according to claim andfurther including inlet and outlet check valve means mounted at theopposite ends of the oil passageway of the housing for passing oilthrough the oil passageway with each reciprocation of said first andsecond pumps. 12. The improvement according to claim 11 wherein thefirst pump comprises:

a diaphragm chamber formed in the pump housing 25 and communicating withthe first cylinder of the first pump; a diaphragm mounted in thediaphragm chamber, the

piston of the firstpump being mounted on the diaphragm for reciprocationin the first cylinder; and means for admitting pressure pulses from thecrankcase of the engine to the diaphragm chamber and therebyreciprocating the piston of the first pump in its pumping cylinderthrough a pumping cycle phragm chamber.

13. In a chain saw of the type including a saw chain and an internalcombustion engine driving the chain and having a crankcase for inductionand precompression of thefuel mixture, the improvement comprising:

a pump housing having first and second cylinders, an

' oil passageway formed between the cylinders, and a pressure passagewayin communication with the engine crankcase, diaphragm mounted in thepressure passageway and reciprocally moveable in response to cyclicalpressure pulses transmitted to the diaphragm from the crankcase,

a first piston in the first cylinder mounted on the diaphragm forreciprocation in the first cylinder through a pumping cycle for each ofthe cyclical pressure pulses transmitted to the diaphragm forcontinuously pumping oil from an oil reservoir to the saw chain andthereby lubricating the chain, and

a second piston mounted for manual reciprocation in r with each pressurepulse admitted to the dia- UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent ,865,213 Dated Februarv 11, 1975 Inven John W.McDermott It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column ne 27, delete "chanber" and sub i therefor --chamber-;

Column 8, line 3h, delete "chain" second occurrence Signed and sealedthis 5th day of April 1.975.

(SEAL) Attest:

C MARSHALL DAI-ZI'I RUTH C. 'L TSON Commissioner of Patents ArrestingOfficer I and Trademarks l FORM PO-10 0 (10-69) uscoMM-Dc cove-Poo i U.S. GOVIIIIIIIIT PRINTING OFFICE Ill, O-lOC-SJ.

1. In a chain saw of the type including a saw chain and an engine fordriving the saw chain and having a crankcase for the induction andprecompression of a fuel/air mixture, an automatic chain oilercomprising: a pump housing including an oil passageway, a pumpingcylinder including a portion common to a portion of the oil passageway,and a diaphragm chamber communicating with the pumping cylinder; inletand outlet check valve means mounted at the opposite ends of the oilpassageway; a piston mounted in the pumping cylinder for reciprocationin the cylinder to pump oil through the oil passageway; a diaphragmmounted in the diaphragm chanber and connected to the piston; means foradmitting pressure pulses from the crankcase of the engine to a firstside of the diaphragm in the diaphragm chamber thereby actuating thediaphragm to reciprocate the piston in the pumping cylinder; and meansfor relieving pressure from a side of the diaphragm opposite the firstside to assist the diaphragm to reciprocate the piston in the cylinder,said piston being mounted on the diaphragm to respond directly to thepressure puLses by reciprocating through a pumping cycle with eachpressure pulse admitted to the diaphragm.
 2. A chain saw oilercomprising: a pump housing detachably secured to a chain saw andincluding an oil passageway extending from one end of the housing to theother, an upstream pumping cylinder having a portion of the oilpassageway extending through it, a downstream pumping cylinder having aportion of the oil passageway extending through it, and a diaphragmchamber communicating with the downstream pumpimg cylinder; inlet andoutlet check valve means mounted at the opposite ends of the oilpassageway of the pump housing; a piston mounted in the upstream pumpingcylinder for manual reciprocation to pump oil through the oil passagewayincluding the portions extending through the upstream and downstreampumping cylinders; a piston supported for reciprocation in thedownstream pumping cylinder to force oil through the oil passageway; adiaphragm mounted in the diaphragm chamber and connected to thedownstream piston; and means for admitting pressure pulses from thechain saw to a first side of the diaphragm in the diaphragm chamber andfor relieving pressure from a side of the diaphragm opposite the firstside thereby actuating the diaphragm to reciprocate the downstreampiston whenever the chain saw is operating, said piston being mounted onthe diaphragm to respond directly to the pressure pulses byreciprocating through a pumping cycle for each pressure pulse introducedto the diaphragm.
 3. The chain saw oiler according to claim 2 furtherincluding: an oil reservoir mounted on the chain saw; an oil inletpassageway extending from the reservoir to the inlet check valve means;and an oil outlet passageway extending from the outlet check valve meansto the chain of the chain saw, said outlet check valve means including acheck valve in the portion of the oil passageway extending through thedownstream pumping cylinder for admitting oil to the oil outletpassageway with each reciprocation of the pistons in the upstream anddownstream pumping cylinders.
 4. In a chain saw of the type including asaw chain and a two-cycle engine for driving the saw chain and having acrankcase for induction and precompression of a fuel/air mixture, achain oiler comprising: an oil reservoir; an oil inlet passagewayincluding a weighted, screened inlet port positioned in the oilreservoir and a flexible conduit extending from the inlet port to aninlet check valve; a pump housing detachably secured to the chain sawand including means for receiving oil from the inlet passageway throughthe inlet check valve; an oil passageway extending through the pumphousing; a pair of pumping cylinders formed in the pump housing and eachincluding a portion of the oil passageway whereby oil flowing throughthe oil passageway flows through portions of both of the pumpingcylinders in series; a piston mounted in the upstream oil passageway forreciprocation into and out of the portion of the upstream pumpingcylinder common to the oil passageway to pump oil through thepassageway; a piston mounted in the downstream pumping cylinder forreciprocation into and out of the portion of the downstream pumpingcylinder common to the oil passageway to pump oil through thepassageway; spring means for normally reciprocating the downstreampiston out of the portion of the downstream pumping cylinder common tothe oil passageway and thereby permitting the flow of oil through thepump housing under the action of the upstream piston; a diaphragmchamber formed in the pump housing and communicating with the downstreampumping cylinder; a diaphragm mounted in the diaphragm chamber andconnected to the downstream piston; relatively large conduit meansextending from the crankcase of the engine to one side of the diaphragmfor applying pressure pulses from the crankcase to the diaphragm andthereby reciprocating the pistOn of the downstream pump against theaction of the spring means; relatively small conduit means extendingfrom the crankcase to the opposite side of the diaphragm for relievingpressure in the diaphragm chamber; outlet check valve means mounted onthe pump housing at the opposite end of the oil passageway from theinlet check valve; and an outlet passageway comprising a conduitextending from the outlet check valve means to a point adjacent the pathof travel of the saw chain.
 5. The chain oiler according to claim 4wherein the downstream piston is operated substantially continuously bypressure pulses from the crankcase of the engine to pump lubricating oilfrom the oil reservoir to the saw chain in sufficient quantity toproperly lubricate the saw chain under normal operating circumstances,and wherein the upstream piston comprises a relatively large pistonadapted for manual operation to prime the downstream pumping cylinder,to purge foreign matter out of the downstream pumping cylinder and topump additional oil from the reservoir to a saw chain in those instancesin which the quantity of oil pumped by the downstream piston isinsufficient to properly lubricate the chain.
 6. In a chain saw of thetype including a saw chain and an internal combustion engine driving thechain and having a crankcase for induction and precompression of thefuel mixture, the improvement comprising: a. a pump housing having firstand second cylinders, an oil passageway formed through the housing andthrough the cylinders formed therein and inlet and outlet check valvemeans mounted at the opposite ends of the oil passageway of the housing;b. a first pump comprising: a piston mounted for reciprocation in saidfirst cylinder driven by pressure pulses in the crankcase of the enginefor continuously pumping oil from an oil reservoir to the saw chain andthereby lubricating the chain, a diaphragm chamber formed in the pumphousing and communicating with the pumping cylinder of the first pump, adiaphragm mounted in the diaphragm chamber and connected to the pistonof the first pump, and means for admitting pressure pulses from thecrankcase of the engine to the diaphragm chamber and therebyreciprocating the piston of the first pump in its pumping cylinder; c. asecond pump having a piston mounted for reciprocation in said secondcylinder, said second pump being located between the oil reservoir andthe first pump in flow communication with the oil passageway, and beingmanually actuated for priming the first pump, for purging foreign matterout of the first pump, and for pumping additional oil to the chainwhenever the oil from the first chain pump is insufficient to properlylubricate the chain; d. a spring positioned between the diaphragm andthe pump housing and thereby biasing the piston of the first pump forreciprocation out of the oil passageway to permit the flow of oiltherethrough; e. a major passageway extending through the pump housingto the side of the diaphragm opposite the spring whereby the diaphragmis responsive to positive pressure pulses in the crankcase toreciprocate the piston into the oil passageway to accomplish a pumpingstroke; and f. a minor passageway extending from the crankcase to thesame side of the diaphragm as the spring whereby pressure in thediaphragm chamber is relieved.
 7. In a chain saw of the type including asaw chain and an engine for driving the saw chain and having a crankcasefor the induction and precompression of a fuel/air mixture, an automaticchain oiler comprising: a pump housing including an oil passageway, apumping cylinder including a portion common to a portion of the oilpassageway, and a diaphragm chamber communicating with the pumpingcylinder; inlet and outlet check valve means mounted at the oppositeends of the oil passageway; a piston mounted in the pumping cylinder forreciprocation into and out of the portion of the cylinder common tO theoil passageway to pump oil through the oil passageway; a diaphragmmounted in the diaphragm chamber and connected to the piston; a springpositioned in the diaphragm chamber for reciprocating the piston out ofthe portion of the pumping cylinder common to the oil passageway andthereby permitting oil through the passageway; and means for admittingpressure pulses from the crankcase to the diaphragm chamber comprising afirst relatively large passageway formed in the pump housing fordirecting pressure pulses from the crankcase to the opposite side of thediaphragm from the spring whereby positive pressure pulses in thecrankcase acting against the diaphragm reciprocate the piston into theportion of the pumping cylinder common to the oil passageway against theaction of the spring, and a second relatively small passageway formed inthe housing and extending to the same side of the diaphragm as thespring for relieving pressure in the diaphragm chamber.
 8. The chainoiler according to claim 7 further including: a second pumping cylinderformed in the pump housing and including a portion common to a portionof the oil passageway, and a second piston mounted in the second pumpingcylinder for manual reciprocation to force oil through the oilpassageway including that portion common to the first pumping cylinderand thereby priming the first cylinder, clearing foreign matter from thefirst pumping cylinder, and supplying quantities of oil to the chain inexcess of those supplied by the operation of the first pump.
 9. Thechain oiler according to claim 8 further including: an oil reservoirmounted on the chain saw; a flexible oil conduit extending from an inletin the oil reservoir to the inlet check valve means; and an oil outletconduit extending from the outlet check valve means to the saw chain.10. In a chain saw of the type including a saw chain and an internalcombustion engine driving the chain and having a crankcase for inductionand precompression of the fuel mixture, the improvement comprising: apump housing having first and second cylinders and an oil passagewayformed through the pump housing between the cylinders and incommunication with an oil reservoir and the saw chain, a first pumphaving a piston in the first cylinder mounted to reciprocate in thefirst cylinder in response to cyclical pressure pulses in the crankcaseof the engine to continuously pump oil from the oil reservoir to the sawchain and thereby lubricate the chain, and a second pump having a pistonmounted for manual reciprocation in the second cylinder located betweenthe oil reservoir and the first pump in flow communication with the oilpassageway, said second pump being selectively actuated to pump oilthrough the oil passageway and the first cylinder for priming the firstpump, for purging foreign matter out of the first pump, and for pumpingadditional oil to the chain whenever the oil from the first pump isinsufficient to properly lubricate the chain.
 11. The improvementaccording to claim 10 and further including inlet and outlet check valvemeans mounted at the opposite ends of the oil passageway of the housingfor passing oil through the oil passageway with each reciprocation ofsaid first and second pumps.
 12. The improvement according to claim 11wherein the first pump comprises: a diaphragm chamber formed in the pumphousing and communicating with the first cylinder of the first pump; adiaphragm mounted in the diaphragm chamber, the piston of the first pumpbeing mounted on the diaphragm for reciprocation in the first cylinder;and means for admitting pressure pulses from the crankcase of the engineto the diaphragm chamber and thereby reciprocating the piston of thefirst pump in its pumping cylinder through a pumping cycle with eachpressure pulse admitted to the diaphragm chamber.
 13. In a chain saw ofthe type including a saw chain and an internal combustion engine drivingthe cHain and having a crankcase for induction and precompression of thefuel mixture, the improvement comprising: a pump housing having firstand second cylinders, an oil passageway formed between the cylinders,and a pressure passageway in communication with the engine crankcase, adiaphragm mounted in the pressure passageway and reciprocally moveablein response to cyclical pressure pulses transmitted to the diaphragmfrom the crankcase, a first piston in the first cylinder mounted on thediaphragm for reciprocation in the first cylinder through a pumpingcycle for each of the cyclical pressure pulses transmitted to thediaphragm for continuously pumping oil from an oil reservoir to the sawchain and thereby lubricating the chain, and a second piston mounted formanual reciprocation in the second cylinder in flow communication withthe oil passageway and located upstream from the first piston to pumpoil through the oil passageway and the first cylinder for manuallypriming the first pump, purging foreign matter out of the first pump,and pumping additional oil to the chain whenever the oil from the firstpump is insufficient to properly lubricate the chain.